package com.wei.base.utils;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.support.v7.widget.AppCompatImageView;
import android.util.AttributeSet;

/**
 * 作者：赵若位
 * 时间：2018/5/4 12:11
 * 邮箱：1070138445@qq.com
 * 功能：圆形的图片
 */

public class CircleImageView extends AppCompatImageView
{
    private float width;
    private float height;
    private float radius;
    private Paint paint;
    private Matrix matrix;

    public CircleImageView(Context context)
    {
        this(context, null);
    }

    public CircleImageView(Context context, AttributeSet attrs)
    {
        this(context, attrs, 0);
    }

    public CircleImageView(Context context, AttributeSet attrs, int defStyleAttr)
    {
        super(context, attrs, defStyleAttr);
        paint = new Paint();
        //设置抗锯齿
        paint.setAntiAlias(true);
        //初始化缩放矩阵
        matrix = new Matrix();
    }

    /**
     * 测量控件的宽高，并获取其内切圆的半径
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width = getMeasuredWidth();
        height = getMeasuredHeight();
        radius = Math.min(width, height) / 2;
    }

    @Override
    protected void onDraw(Canvas canvas)
    {
        //将着色器设置给画笔
        paint.setShader(initBitmapShader());
        //使用画笔在画布上画圆
        canvas.drawCircle(width / 2, height / 2, radius, paint);
    }

    /**
     * 获取ImageView中资源图片的Bitmap，利用Bitmap初始化图片着色器,通过缩放矩阵将原资源图片缩放到铺满整个绘制区域，避免边界填充
     */
    private BitmapShader initBitmapShader()
    {
        Bitmap bitmap = ((BitmapDrawable) getDrawable()).getBitmap();
        BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
        float scale = Math.max(width / bitmap.getWidth(), height / bitmap.getHeight());
        //将图片宽高等比例缩放，避免拉伸
        matrix.setScale(scale, scale);
        bitmapShader.setLocalMatrix(matrix);
        return bitmapShader;
    }

}
